KR20150014984A - Engine exhaust-gas purification device - Google Patents

Abstract

Provided is an engine exhaust gas purifying apparatus capable of achieving regulation of exhaust gas in response to a ship side even when a conventional fuel is used instead of a low sulfur fuel. An engine exhaust gas purifying apparatus 1 for reducing and removing atmospheric pollutants in the exhaust gas discharged from the main engine 10 is disposed in the exhaust system L1 of the main engine 10 to regulate the total amount of the exhaust gas An exhaust gas recycling apparatus 60 for exhausting a part of the exhaust gas introduced as recirculation exhaust gas from the downstream of the exhaust gas scrubber 40 to the main engine 10 again, .

Description

{ENGINE EXHAUST-GAS PURIFICATION DEVICE}

The present invention relates to an engine exhaust gas purifying apparatus applied to a diesel engine or the like of a main engine (main engine) for ships, for example.

Diesel engines, which are main engines for ships, are in a situation where emissions regulations for sulfur oxides (SOx) and nitrogen oxides (NOx) applied to ships are tightened. For this reason, sulfur (S) in the fuel is regulated in the future.

However, in the present situation, the desulfurization apparatus of the fuel maker is not sufficient, and therefore, the production capacity of the fuel satisfying the standard is expected to be insufficient. For this reason, low-sulfur fuel satisfying the standard is insufficient, and there is a fear of an increase in the shipping cost accompanying the rise of the fuel price. Regarding the regulation of sulfur oxides, instead of reducing the sulfur content on the fuel side, it is also possible to use an engine exhaust gas purifying device or the like on the ship side.

On the other hand, in a diesel engine of a ship main engine, as a technique for reducing nitrogen oxides in the exhaust gas, there is a technique in which a part of the exhaust gas after combustion is introduced and introduced into the air supply side, and exhaust gas recirculation (EGR: Recirculation is known.

Background Art [0002] Conventional technologies related to exhaust gas recirculation (hereinafter referred to as " EGR ") include, for example, an exhaust gas cleaning device called a scrubber, as in Patent Documents 1 and 2 below. In these conventional technologies, a part of the exhaust gas used for EGR is thoroughly cleaned through the scrubber.

[Prior Art Literature]

[Patent Literature]

(Patent Document 1) Japanese Patent Publication No. 3304090

(Patent Document 2) Japanese Laid-Open Patent Publication No. 2002-332919

The prior art described in the above-mentioned patent documents has a scrubber, but does not treat the entire amount of exhaust gas discharged from the diesel engine, but treats a part of the exhaust gas introduced for EGR. Therefore, in the configuration of the prior art, it is possible to reduce the nitrogen oxide of the exhaust gas discharged from the diesel engine by EGR, but it has not been possible to reduce the sulfur oxides in the exhaust gas.

That is, although the conventional scrubber for cleaning the exhaust gas for EGR is effective for reducing the emission amount of nitrogen oxides, it can not cope with reduction of the emission amount of sulfur oxides. Therefore, instead of reducing the sulfur content on the fuel side, It can not be used as an engine exhaust gas purifying device.

From such a background, it is possible to reduce both sulfur oxides and nitrogen oxides in the exhaust gas discharged from the diesel engine serving as the main engine for the ship, and to deal with exhaust gas regulations applied to the ship, It is desired to develop an engine exhaust gas purifying apparatus which can be achieved only by the use of the exhaust gas purifying apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an engine exhaust gas purification system capable of achieving exhaust gas regulation by a ship- And to provide a device.

In order to solve the above problems, the present invention adopts the following means.

An engine exhaust gas purifying apparatus according to the present invention is an engine exhaust gas purifying apparatus for reducing and eliminating harmful substances in exhaust gas discharged from a main engine for a ship, the engine exhaust gas purifying apparatus comprising: And an exhaust gas recirculation device for supplying a part of the exhaust gas introduced as exhaust gas for recirculation from the downstream of the exhaust gas scrubber to the main engine for ship again .

According to such an engine exhaust gas purifying apparatus, there is provided an exhaust gas purifying apparatus which is disposed in an exhaust system of a main engine for a ship and cleans the entire amount of the exhaust gas, and an exhaust gas purifier which is introduced from the downstream side of the exhaust gas purifier as a recirculating exhaust gas The sulfur oxides in the exhaust gas are dissolved and removed in the cleaning liquid by passing through the exhaust gas cleaning device and the nitrogen oxides in the exhaust gas are removed from the exhaust gas by the exhaust gas recirculation device , The exhaust gas recirculation device reduces the oxygen concentration in the air supply so that generation in the engine is suppressed and reduced.

Also, with respect to soot in the exhaust gas, since the entire amount of the exhaust gas passes through the exhaust gas scrubber and is subjected to the cleaning treatment, it is removed together with the sulfur oxide.

In the above invention, it is preferable that the marine main engine includes an exhaust turbine supercharger, and the exhaust gas recirculation device is provided with a flow control valve for regulating the amount of introduction of the recirculating exhaust gas and a recirculating exhaust gas recirculating device It is preferable that the recirculating exhaust gas is supplied to the compressor portion of the exhaust turbine turbocharger and is compressed together with fresh air. As a result, the exhaust gas for recirculation to be regulated by the flow rate control valve is passed through the exhaust gas scrubber to lower the temperature, so that the flow rate control valve of the low temperature specification can be used.

In this case, it is preferable that the exhaust gas recirculation device includes an air blowing part for increasing the recirculated exhaust gas as necessary. That is, even in an engine exhaust gas purifying apparatus in which the pressure loss is large when the exhaust gas for recirculation is supplied to the compressor section of the exhaust turbine turbocharger, the boosting by the blowing section is possible. Thereby, the exhaust gas for recirculation is reliably supplied to the compressor portion through the recirculating heat exchanger.

In the above invention, the marine main engine is provided with an exhaust turbine supercharger, the exhaust gas recirculation device further includes a flow control valve for regulating the introduction amount of the recirculated exhaust gas and a blower for increasing the recirculation exhaust gas And the recirculating exhaust gas is supplied between an air cooler for cooling the air supply unit and a compressor unit of the exhaust turbine turbocharger. As a result, the exhaust gas for recirculation to be regulated by the flow rate control valve is passed through the exhaust gas scrubber to lower the temperature, so that the flow rate control valve of the low temperature specification can be used. In addition, since the recirculating exhaust gas is supplied between the compressor portion of the exhaust turbine turbocharger and the air cooler that cools the air supply, a recirculating heat exchanger for cooling the recirculating exhaust gas becomes unnecessary.

According to the engine exhaust gas purifying apparatus of the present invention described above, the sulfur oxides and the nitrogen oxides in the exhaust gas discharged from the main engine for ship can be removed / reduced, so that even when conventional fuels containing a large amount of sulfur are used, It is possible to cope with enhancement of exhaust gas regulation. Therefore, it is possible to reduce the operating cost by using the inexpensive conventional fuel, and it becomes unnecessary to switch the fuel or the apparatus in the regulated sea area and other sea areas.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing an outline structure of an engine exhaust gas purifying apparatus according to the present invention, which is inserted into an intake and exhaust system of a main engine, which is mainly a main engine of a ship; FIG.
Fig. 2 is a schematic structural view showing a first modified example of the engine exhaust gas purifying apparatus shown in Fig. 1. Fig.
Fig. 3 is a view showing a schematic configuration in which the engine exhaust gas purifying apparatus according to the present invention is inserted into an intake and exhaust system of a main engine, which is mainly a main engine of a ship.

Hereinafter, an embodiment of an engine exhaust gas purifying apparatus according to the present invention will be described with reference to Fig. 1 is a structural example inserted in a main engine intake / exhaust system which is mainly a ship main engine.

(Hereinafter referred to as " purifier ") 1 shown in Fig. 1 is an apparatus for purifying exhaust gas of a main engine (for example, a diesel engine) (Air pollutants) such as sulfur oxides and nitrogen oxides.

A main engine 10 for propelling a ship is mounted in the vessel, and exhaust gas discharged from the main engine 10 is discharged from the chimney to the atmosphere.

The main engine 10 is constituted by a plurality of cylinders 11, an air supply manifold 12 and an exhaust manifold 13. Fuel supplied from a fuel supply system (not shown) is injected into each cylinder 11. This fuel is burned in the cylinder 11 by the oxygen in the air supply supplied from the air supply manifold 12 so that in the main engine 10 the thermal energy held by the fuel is converted into the engine output, Is generated.

The exhaust gas generated in each cylinder 11 is collected in the exhaust manifold 13 and is led to the chimney through the exhaust system L1. A turbine section 21 of an exhaust turbine turbocharger 20, an exhaust gas economizer 30 and an exhaust gas scrubber 40 are formed in this exhaust system L1.

The exhaust turbine turbocharger 20 is a device that compresses the supply air by driving the compressor unit 22 by rotating the turbine unit 21 at a high speed by using the energy (kinetic energy and thermal energy) to be. Reference numeral 23 in the drawing denotes a rotary shaft connecting between the turbine section 21 and the compressor section 23.

The exhaust gas economizer 30 is a heat exchanger for generating steam by exchanging heat between the exhaust gas discharged from the main engine 10 and the water supplied by the water supply pipe 31. That is, the exhaust gas economizer 30 is a device for recovering heat energy of the exhaust gas to obtain steam in order to effectively utilize the thermal energy held by the exhaust gas.

The exhaust gas cleaning device 40 is a device for removing harmful substances contained in the exhaust gas and uses liquid such as water as a cleaning liquid to collect sulfur oxide and particles in the exhaust gas into droplets or liquid film of the cleaning liquid and separate them . In this case, since the exhaust gas to be treated in the exhaust gas scrubber 40 passes through the exhaust turbine turbocharger 20 and the exhaust gas economizer 30, the pressure is lowered and the temperature is slightly lowered, Therefore, reliability and durability of the exhaust gas scrubber 40 are enhanced.

The air supply manifold 12 is connected to an air supply system L2 having an air compressor (intercooler) 50 and a compressor unit 22 of an exhaust turbine turbocharger 20. Therefore, the supply air introduced from the air supply system L2 is supplied to each cylinder 11 from the air supply manifold 12.

The air cooler 50 is a heat exchanger for cooling the air supply unit whose temperature has been increased by the compression of the turbocharger and is effective for improving the fuel efficiency and the output of the main engine 10. [ Reference numeral 51 in the drawing denotes a water supply pipe for supplying cooling water for the cooling medium.

An exhaust gas recirculation system L3 (hereinafter referred to as "EGR system") constituting an exhaust gas recirculation system 60 is formed by branching from the exhaust system L1 on the downstream side of the exhaust gas scrubber 40 .

The EGR system L3 is provided with a flow control valve 70 for regulating the introduction amount of recirculation exhaust gas (hereinafter referred to as "EGR gas"), a recirculation heat exchanger for cooling the EGR gas (Hereinafter referred to as " substrate ") 80 is formed. The EGR system L3 of the present embodiment is connected to the compressor section 22 of the exhaust turbine turbocharger 20 so that the compressor section 22 is configured to compress EGR gas together with fresh air .

The flow rate control valve 70 controls the degree of opening according to the output control of the main engine 10 or the like and adjusts the amount of EGR gas introduced from the exhaust system L1 into the EGR system L3.

In this case, since the EGR gas to be regulated by the flow control valve 70 has passed through the exhaust gas scrubber 40, it is cooled by the cleaning liquid and becomes relatively low in temperature. For this reason, the flow control valve 70 can be of a low-temperature specification, which is advantageous in terms of cost and reliability as well as durability. Since the EGR gas to be regulated by the flow control valve 70 is also removed from the exhaust gas scrubber 40 by particles such as soot, the possibility of particle sticking is also lowered, and therefore, .

The EGR heat exchanger 80 is a heat exchanger that cools the EGR gas by heat exchange with the cooling water supplied from the water supply pipe 81. By using the EGR gas cooled in the EGR heat exchanger 80, the fresh air and the EGR air compressed by the compressor section 22 become low temperature / high density, and therefore, the compression efficiency of the compressor section 22 is improved.

As described above, the purifier 1 according to the present embodiment is a device for reducing and removing harmful substances in the exhaust gas discharged from the main engine for ship, and is arranged in the exhaust system L1 of the main engine 10, An exhaust gas recycling apparatus 40 for exhausting a part of the exhaust gas introduced as EGR gas from the downstream of the exhaust gas scrubber 40 to the main engine 10, (60). That is, in the present embodiment, the exhaust system L1 on the downstream side of the exhaust gas economizer 30 described above and the EGR system L3 branching from the exhaust system L1 are constituted by the configuration of the prior art .

Such a purifier 1 is configured such that the exhaust gas purifier 40 disposed in the exhaust system L1 of the main engine 10 is configured to perform a cleaning process on the entire amount of the exhaust gas, The particles such as sulfur oxides and soot in the exhaust gas are removed. Therefore, on the downstream side of the exhaust gas scrubber 40, the sulfur oxides contained in the exhaust gas are reduced, and the reference value of the exhaust gas regulation applied to the ship can be cleared from the chimney to the atmosphere.

That is, a clean exhaust gas that does not exceed the reference value of the exhaust gas regulation relating to sulfur oxides can be discharged without using the low sulfur fuel that meets the criterion on the fuel side as the fuel of the main engine 10. [ In other words, with respect to the regulation of sulfur oxides, since it is possible to cope with regulations on the ship side using the purifier 1 of the present embodiment instead of reducing the sulfur content on the fuel side, .

In addition, since the exhaust gas recirculation device 60 that supplies a part of the exhaust gas introduced as the EGR gas to the main engine 10 from the downstream of the exhaust gas scrubber 40 is provided again, The exhaust gas recirculation device 60 reduces the oxygen concentration in the supply air as in the prior art.

Therefore, the exhaust gas discharged from the chimney to the atmosphere can satisfy the regulations of the ship's exhaust gas regarding sulfur oxides, nitrogen oxides, particles, and the like.

In the purifier 1 of the present embodiment, the main engine 10 is provided with an exhaust turbine turbocharger 20, and the exhaust gas recirculation device 60 is provided with a flow control valve (70) and an EGR heat exchanger (80) for cooling the EGR gas. Further, the cooled EGR gas is supplied to the compressor section 22 of the exhaust turbine turbocharger 20 and is configured to be compressed together with fresh air.

As a result, the EGR gas to be regulated by the flow control valve 70 passes through the exhaust gas scrubber 40 and the temperature is lowered, and the sulfur oxide and particles are removed. Therefore, it becomes possible to use the flow control valve 70 of the low-temperature specification, and the problem caused by the sulfur oxide or the particles does not occur well.

The exhaust gas economizer 30 described above is disposed near the chimney in the vicinity of the main engine 10 in the exhaust gas scrubber 40 depending on the layout constraint in the ship The distance to the installed exhaust turbine turbocharger 20 becomes longer. As a result, it is considered that the pipe length of the EGR system L3 becomes longer, and the pressure loss of the EGR gas increases.

In such a case, the purifier 1A of the modification shown in FIG. 2 has the exhaust gas recirculation unit 60A formed with the blowing unit 90 for increasing the EGR gas as required. In addition, the illustrated blower 90 is a blower driven by the electric motor 91.

In addition, even in the purifying device 1A of the arrangement in which the pressure loss when the EGR gas is supplied to the compressor section 22 of the exhaust turbine turbocharger 20 is increased by additionally providing the blowing section 90, So that the EGR gas passes through the EGR heat exchanger 80 and is reliably supplied to the compressor section 22. [

In the modification shown in Fig. 2, the same parts as those in the embodiment of Fig. 1 described above are denoted by the same reference numerals, and a detailed description thereof will be omitted.

Next, another embodiment according to the present invention will be described with reference to Fig. The same reference numerals are given to the same components as those in the above-described embodiment and modifications, and a detailed description thereof will be omitted.

In this embodiment, the main engine 10 includes an exhaust turbine turbocharger 20. The exhaust gas recirculation device 60B includes a flow control valve 70 for regulating the amount of EGR gas introduced, (90). The EGR gas boosted by the blowing section 90 is supplied to the air supply system L2 through the EGR system L3 '. EGR gas in this case is supplied between the compressor 22 of the exhaust turbine turbocharger 20 and the air cooler 50 which cools the air supply in the air supply system L2.

When such a configuration is employed, sulfur oxides are treated in the same manner as in the above-described embodiment. Further, since the EGR gas to be regulated by the flow control valve 70 passes through the exhaust gas scrubber 40 and the temperature of the EGR gas is lowered, the flow control valve 70 of the low temperature specification is used as in the above- .

In the present embodiment, since the EGR gas is supplied between the compressor unit 22 of the exhaust turbine turbocharger 20 and the air cooler 50 that cools the supply air, the EGR heat exchanger 80 for cooling the EGR gas is unnecessary It becomes. That is, the compressor unit 22 according to the present embodiment compresses only new air, and the new air after compression joins the EGR gas boosted by the blowing unit 90 into the air supply system L2, And is then supplied to the supply manifold 12. [ Further, in such a configuration, it is indispensable to raise the EGR gas by the blowing section 90 in order to join the EGR gas to the new air after the booster.

The total amount of the exhaust gas passes through the exhaust gas cleaning device 40 and the exhaust gas recirculation devices 60, 60A, 60B, The sulfur oxides and the nitrogen oxides in the exhaust gas discharged from the main engine 10 can be removed / reduced. Therefore, it is possible to cope with the enhancement of the exhaust gas regulation applied to the ship, even if conventional fuels having a larger amount of sulfur than the fuel of the new standard are used. Therefore, it is possible to reduce the running cost by using the cheap conventional fuel, The conversion of the fuel or the apparatus becomes unnecessary in the sea area and the other sea area.

Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within a range not departing from the gist of the present invention.

1, 1A, 1B: Engine exhaust gas purifier (purifier)
10: Main engine (main engine for ship propulsion)
11: Cylinder
12: Supply manifold
13: Exhaust manifold
20: exhaust turbine supercharger
21: turbine section
22:
30: Exhaust gas economizer
40: Exhaust gas cleaning device
50: air cooler
60, 60A, 60B: Exhaust gas recirculation device
70: Flow control valve
80: recirculation heat exchanger (EGR heat exchanger)
90:
L1: Exhaust system
L2: Supply system
L3, L3 ': Exhaust gas recirculation system (EGR system)

Claims (3)

An engine exhaust gas purifying apparatus for reducing and removing atmospheric pollutants in an exhaust gas discharged from a ship main engine,
An exhaust gas cleaning device arranged in the exhaust system of the main engine for ship to clean the entire amount of the exhaust gas and a part of the exhaust gas introduced as recirculation exhaust gas from the downstream of the exhaust gas cleaner, And an exhaust gas recirculation device for supplying the exhaust gas back to the main engine,
Wherein the marine main engine includes an exhaust turbine supercharger,
Wherein the exhaust gas recirculation device includes a flow rate control valve for regulating an amount of introduction of the recirculated exhaust gas,
And the recirculating exhaust gas is supplied to a compression section of the exhaust turbine turbocharger and is compressed together with fresh air. The method according to claim 1,
And the exhaust gas recirculation device includes a recirculation heat exchanger for cooling the recirculation exhaust gas. 3. The method according to claim 1 or 2,
Wherein the exhaust gas recirculation device includes an air blowing part for increasing the recirculated exhaust gas.

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